SCS-C02 Threat Detection and Incident Response Practice Test 13 — 15 Questions

Question 1

A company has a security rule that all S3 buckets must have server access logging enabled. A security engineer uses AWS Config to evaluate compliance. The engineer configures a managed rule but notices that the rule does not evaluate all buckets. What is the most likely reason?

Choose an answer to begin — your selection is scored in the full session.

Accepted Answer

The rule only evaluates buckets that have a specific tag.. The AWS Config managed rule `s3-bucket-server-access-logging-enabled` can be configured with a `tag` parameter. When a tag is specified, the rule only evaluates S3 buckets that have that exact tag key-value pair. If the security engineer did not apply the required tag to all buckets, or if the rule was configured with a tag that does not match all buckets, some buckets will be excluded from evaluation, causing the observed behavior.

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The rule only evaluates buckets in the us-east-1 region.

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The rule excludes buckets that have a bucket policy denying access to AWS Config.

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The rule requires the logging target bucket to be in the same account.

Question 2

A security engineer is reviewing a CloudTrail log entry (exhibit). What is the most immediate security concern indicated by this event?

Accepted Answer

A security group rule was added allowing SSH access from any IP address.. The CloudTrail log shows an AuthorizeSecurityGroupIngress API call that added a security group rule with the CIDR 0.0.0.0/0 for port 22 (SSH). This effectively opens SSH access to the entire internet, creating a severe exposure that could allow any attacker to attempt brute-force or credential-stuffing attacks against any EC2 instance associated with that security group. This is the most immediate security concern because it directly introduces a wide-open attack surface.

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The source IP address 203.0.113.5 is from a known malicious IP range.

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The API call was made from the AWS CLI, which may indicate a compromised access key.

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The user JohnDoe did not use multi-factor authentication (MFA) for this API call.

Question 3

A company runs a critical web application on Amazon EC2 instances behind an Application Load Balancer (ALB) in a VPC. The security team uses Amazon GuardDuty and has enabled Amazon Detective. Recently, GuardDuty raised a 'Recon:EC2/PortProbeUnprotectedPort' finding for one of the instances. The security engineer verified that the ALB security group only allows inbound HTTP/HTTPS from the internet. However, the finding indicates that the instance is receiving probes on port 22 (SSH). Further investigation with Detective shows that the probes originate from multiple IP addresses and are reaching the instance's private IP address. The engineer suspects that the SSH port is exposed despite the security group configuration. What is the MOST likely cause of this exposure?

Accepted Answer

The EC2 instance's security group allows inbound SSH from 0.0.0.0/0.. The GuardDuty finding 'Recon:EC2/PortProbeUnprotectedPort' indicates that an EC2 instance is receiving unsolicited probes on a port that should not be publicly accessible. Since the ALB security group only allows HTTP/HTTPS from the internet, but the probes are reaching the instance's private IP on port 22 (SSH), the most likely cause is that the instance's own security group has an inbound rule allowing SSH from 0.0.0.0/0. This bypasses the ALB's security group because the instance's security group is evaluated independently for direct traffic to the instance's private IP, and if it permits SSH from anywhere, the probes will reach the instance.

Answer

VPC Flow Logs are misconfigured and are inadvertently forwarding traffic to the instance.

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AWS Shield Advanced is causing false positives by marking legitimate traffic as probes.

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The ALB security group has an inbound rule that allows SSH from the internet.

Question 4

A security engineer is investigating a potential compromise. An EC2 instance running Amazon Linux 2 is sending outbound traffic to a known malicious IP address. The engineer needs to capture the network traffic for analysis without alerting the attacker. Which solution meets these requirements?

Accepted Answer

Use VPC Traffic Mirroring to mirror the EC2 instance's ENI traffic to a monitoring appliance in a separate VPC.. VPC Traffic Mirroring captures all network traffic at the packet level from the EC2 instance's Elastic Network Interface (ENI) and forwards it to a monitoring appliance without any inline processing or modification of the traffic. This allows the security engineer to perform deep packet analysis while remaining completely transparent to the attacker, as the mirrored traffic is a copy and does not affect the original flow. Unlike other options, Traffic Mirroring provides full packet capture (including headers and payloads) for forensic analysis, which is essential for investigating a compromise.

Answer

Enable VPC Flow Logs on the ENI and stream to Amazon S3 for analysis.

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Attach a security group to the instance that logs all traffic to CloudWatch Logs.

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Enable AWS Network Firewall on the VPC and configure a rule to log all traffic to the malicious IP.

Question 5

Drag and drop the steps to implement a secure CI/CD pipeline with AWS CodePipeline and IAM in the correct order.

Accepted Answer

First, create IAM roles with least privilege for CodePipeline and CodeBuild. Then, create an encrypted S3 bucket for storing artifacts. Next, create a source repository (e.g., AWS CodeCommit). After that, create a build project configured with security scanning tools. Finally, create the CodePipeline that integrates the source, build, and deployment stages.. Secure pipeline requires encrypted artifact bucket, IAM roles, source repo, build project with security scanning, and pipeline.

Answer

First, create an encrypted S3 bucket. Then, create a source repository. Next, create IAM roles. After that, create a build project with security scanning. Finally, create the pipeline.

Answer

First, create the pipeline. Then, create a source repository. Next, create a build project with security scanning. After that, create IAM roles. Finally, create an encrypted S3 bucket.

Answer

First, create a source repository. Then, create a build project with security scanning. Next, create IAM roles. After that, create the pipeline. Finally, create an encrypted S3 bucket.

Question 6

A security engineer notices that an IAM role used by an EC2 instance is generating a large number of API calls to an S3 bucket that is not part of the company's account. Which AWS service should be used to detect and alert on this suspicious activity?

Accepted Answer

Amazon GuardDuty. Amazon GuardDuty is the correct service because it uses machine learning and anomaly detection to analyze AWS CloudTrail management and data events, VPC Flow Logs, and DNS logs. It can detect unusual API calls, such as an EC2 instance role making a high volume of requests to an S3 bucket outside the company's account, which is a classic indicator of compromised credentials or data exfiltration. GuardDuty generates findings and can integrate with Amazon CloudWatch Events to trigger alerts or automated remediation.

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AWS CloudTrail

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Amazon Inspector

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AWS Config

Question 7

A security engineer needs to detect and alert on suspicious API calls made from a compromised EC2 instance. The instance is associated with an IAM role that has permissions to call various AWS APIs. Which AWS service should the engineer use to monitor API calls and trigger alerts?

Accepted Answer

AWS CloudTrail combined with Amazon CloudWatch Events. AWS CloudTrail records all API calls made by or on behalf of the EC2 instance's IAM role. By sending these logs to Amazon CloudWatch Events (now Amazon EventBridge), you can create rules that match specific API actions (e.g., 'ec2:TerminateInstances') and trigger alerts via SNS, Lambda, or other targets. This combination provides real-time monitoring and alerting for suspicious API activity from a compromised instance.

Answer

Amazon GuardDuty

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AWS Config

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VPC Flow Logs

Question 8

A company uses AWS Organizations with multiple accounts. The security team wants to centrally collect and analyze CloudTrail logs from all accounts in a single S3 bucket. What is the most efficient way to achieve this?

Accepted Answer

Create a single organization trail in the management account that logs all accounts.. AWS Organizations supports creating a single organization trail in the management account that automatically logs CloudTrail events for all accounts in the organization. This centralizes log collection into one S3 bucket without needing to configure trails per account, making it the most efficient and scalable approach for multi-account environments.

Answer

Create a CloudTrail trail in each account and configure the same S3 bucket as the destination.

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Use CloudWatch Logs subscription filter to send logs from each account to a central account.

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Use S3 cross-region replication to copy logs from each account's bucket to a central bucket.

Question 9

During an incident response, a security engineer needs to capture a forensic image of an EC2 instance's root volume for analysis. The instance is running and cannot be stopped. What is the recommended approach to capture the volume without stopping the instance?

Accepted Answer

Create a snapshot while the volume is attached to the instance.. The correct approach is to create a snapshot of the EBS root volume while it is still attached to the running instance (Option C). Snapshots can be taken of in-use volumes without stopping the instance, providing a point-in-time copy for forensic analysis. Option B is incorrect because you cannot detach the root volume of a running instance without first stopping it, which contradicts the requirement not to stop the instance.

Answer

Use the dd command via AWS Systems Manager to create a raw image and store it in S3.

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Detach the volume from the instance, create a snapshot, and then attach it to a forensic analysis instance.

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Use AWS Systems Manager to run a command that copies the volume content to S3.

Question 10

A company uses Amazon GuardDuty and receives a finding of type 'Backdoor:EC2/C&CActivity.B!DNS' for an EC2 instance. What does this finding indicate?

Accepted Answer

The instance is communicating with a known command and control server.. The finding 'Backdoor:EC2/C&CActivity.B!DNS' indicates that GuardDuty has detected DNS queries from the EC2 instance to a domain associated with known command and control (C&C) infrastructure. This is based on GuardDuty's threat intelligence feeds that map DNS request patterns to known malicious domains, signaling that the instance may be compromised and communicating with an attacker's server.

Answer

The instance is being targeted by an SSH brute force attack.

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The instance is exfiltrating data to an S3 bucket.

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The instance is being used in a DDoS attack.

Question 11

Which AWS service can be used to detect and alert on suspicious network traffic patterns within a VPC, such as port scanning or unusual outbound traffic?

Accepted Answer

Amazon GuardDuty. Amazon GuardDuty is a threat detection service that continuously monitors VPC Flow Logs, DNS logs, and CloudTrail events to identify suspicious network traffic patterns such as port scanning, unusual outbound traffic, and other malicious activities. It uses machine learning, anomaly detection, and integrated threat intelligence to generate security alerts without requiring manual rules or signatures.

Answer

AWS WAF

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AWS Network Firewall

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VPC Flow Logs

Question 12

During an incident response, a security engineer needs to preserve the state of an EC2 instance for forensic analysis. The instance is running a production workload that cannot be interrupted. Which of the following actions should the engineer take FIRST to ensure data integrity?

Accepted Answer

Use AWS Systems Manager Run Command to create a memory dump and store it in S3.. During an incident response, preserving volatile data (such as memory contents) is critical before any other action that might alter the system state. AWS Systems Manager Run Command can execute a command (e.g., using `dd` or `LiME`) to capture a memory dump and store it in Amazon S3 without interrupting the production workload. This ensures that forensic artifacts like running processes, network connections, and encryption keys are preserved before any disk-level operations that could overwrite or modify evidence.

Answer

Run the dd command to clone the root volume to another EBS volume.

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Create an AMI from the instance while it is running.

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Take a snapshot of the attached EBS volumes while the instance is running.

Question 13

A security engineer is investigating a potential data exfiltration from an S3 bucket. Which AWS service should be used to analyze the VPC Flow Logs for the S3 bucket's endpoint?

Accepted Answer

Amazon Detective. Amazon Detective is the correct service because it can ingest and analyze VPC Flow Logs, including those for a VPC endpoint used to access an S3 bucket. Detective uses machine learning, statistical analysis, and graph theory to identify the root cause of suspicious network traffic patterns, such as unusual data volumes or connections to external IPs, which are indicative of data exfiltration.

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Amazon Macie

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Amazon Inspector

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Amazon GuardDuty

Question 14

A security engineer needs to ensure that all API calls in an AWS account are logged for incident response. Which AWS service should be enabled?

Accepted Answer

AWS CloudTrail. AWS CloudTrail is the correct service because it records all API calls made in an AWS account, including the identity of the caller, the time of the call, the source IP address, and the request parameters. This logging is essential for incident response to reconstruct events and identify unauthorized or malicious activity.

Answer

Amazon GuardDuty

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VPC Flow Logs

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AWS Config

Question 15

An organization uses AWS Organizations and wants to centrally manage Amazon GuardDuty across multiple accounts. What is the correct architecture?

Accepted Answer

Designate a delegated administrator account in Organizations and enable GuardDuty in that account.. AWS Organizations allows you to designate a delegated administrator account for Amazon GuardDuty, which can then centrally manage GuardDuty across all member accounts in the organization. This architecture simplifies enabling GuardDuty and managing findings without needing to configure each account individually, as the delegated administrator can enable GuardDuty for all accounts in the organization from a single point.

Answer

Enable GuardDuty only in the master account; it will automatically monitor all member accounts.

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Use AWS CloudFormation StackSets to deploy GuardDuty in all accounts and regions.

Answer

Enable GuardDuty in each region separately and use cross-region aggregation.